The Earth, the Solar System, the Milky Way and several thousand of the closest galaxies to us are in a kind of “bubble”, an area of space with a diameter of about 250 million light years, inside which the density of matter is two times lower than in the rest of our universe. This hypothesis was put forward by Lucas Lombriser, a professor of theoretical physics from the University of Geneva (UNIGE), and it, this assumption, is a solution to the puzzle, which divided the scientific community into two camps for a decade. This riddle, in turn, is connected with the answer to the question “at what speed does the Universe expand?”, And two independent methods used to determine this speed yielded two results, the values of which differed by approximately 10 percent, by a value sufficient for occurrence strong contradictions.
The universe began to expand immediately after the Big Bang, which occurred about 13.8 billion years ago. This assumption was first made by the Belgian physicist Georges Lemaitre and confirmed by the American astronomer Edwin Hubble in 1929, which showed that most of the galaxies farthest from us move faster than necessary. The calculations associated with this observation showed that all the observed galaxies were initially located at one point in space, which corresponds to the place of the Big Bang. These studies gave the world the Hubble-Lemetre law and the so-called Hubble constant (H0), the value of which is the rate of expansion of the Universe.
For all time, the H0 value has been constantly updated and now it is approximately 70 km/s per megaparsec. However, as mentioned above, there are two independent methods for measuring H0 that give conflicting results.
The first method is based on the analysis of relict cosmic microwave background. This background is microwave radiation that permeates the entire space of the Universe, which is the “cooled” light emitted at the moment after 370 thousand years from the Big Bang. Using the data array collected by the Planck mission apparatus, and taking into account that the Universe is homogeneous and isotropic, using the formulas and equations of Einstein’s theory, the value of H0 equal to 67.4 was obtained.
The second method is based on observations of supernova explosions that occasionally occur in neighboring galaxies. These “bright” cosmic cataclysms make it possible to determine distances with very high accuracy, which was used for calculating H0, which gave a result equal to 74.
“Both values were constantly refined, preserving their contradictory difference. This difference divided the scientific community into two camps and caused the emergence of a number of theories, some of which indicate the presence and influence of some “new physics” so far unknown to us,” says Lucas Lombrizer, – “However, the explanation of this fact can be very simple and exclude the “new physics”, if we assume that the Universe is not as homogeneous as previously thought. In other words, matter in the Universe can be distributed unevenly but also form areas with low and high concentrations”.
“If we are inside a giant bubble with a density of matter much lower than the density in the rest of the Universe, this will affect the accuracy of measuring distances using the supernova method and, of course, the accuracy of determining the value of the constant H0”, Lucas Lombrezer explains his assumption.
All that is needed to explain the difference in the H0 values obtained by the two methods is that the sizes of this “Hubble bubble” were large enough to include our galaxy and a galaxy in which supernovae are used to measure distances. Assuming the size of this bubble to be 250 million light-years and half the density of matter in it, Lucas Lombrizer calculated that the values of H0 obtained by analyzing the microwave background and the method of measuring distances almost coincide.
“The calculated by me probability of the existence of fluctuations in the density of matter on such a scale has such a value that indicates that all this is real, and not just a theoretical fantasy”, says Lucas Lombriser, “And there can be many more in the vast expanses of the Universe similar areas”.